Panini (Pāṇini) was an ancient Hindu Indian grammarian (approximately 5th century BC) who is most famous for formulating 4,000 rules of Sanskrit morphology.

Panini's grammar of Sanskrit is highly systematized and relies on patterns found in the language. Features of language are categorized according to their similarities, and then form the subject matter of the set of ordered morphological rules which constitute the bulk of the work. Inherent in the analytic approach employed by Panini are the concepts of the phoneme and the morpheme, only recognized by Western linguists millennia after he used them. The Paninian grammar is notably descriptive; it does not attempt to tell people how they should speak and write; Panini was only concerned with what people actually did say and write.

Panini's rules are said to be perfect - that is, they perfectly describe the Sanskrit morphology, and regarded as so clear that computer scientists have made use of them to teach computers to understand Sanskrit.

Panini uses metarules, transformations, and recursion in such sophistication that his grammar has the computing power equivalent to a Turing machine. In this sense Panini may be considered the father of computing machines. Paninian grammars have been devised for non-Sanskrit languages also. The Backus-Naur Form or BNF grammars used to describe modern programming languages have significant similarities with Panini's grammar rules.

One of Panini's methods of demonstrating linguistic structures and behavior was to create analyses of various ancient Hindu scriptures, such as the Shiva Sutras. By formulating a logic based on the Sanskrit morphology, he was able to analyze existing scripture and show its inherent formations in accordance with his stated principles.

Panini was very much part of early Hindu Vedic culture, since Sanskrit was the language of the Vedas.

According to Shaina Bal in a study of Panini:

" Panini was born in Shalatula, an area on the Indus river in present day Pakistan. Experts give dates ranging from as early as the 4th century BC. The consensus of opinion has fixed his date not later than the 5th century B.C. At that period sacrifice and the worship of various deities were current and popular, and theistic devotion to particular divinities, generally expressed by the term Bhakti, had become prevalent. Panini refers to Vasudev as the object of devotion, and Paramatma Devata Visesa, a form of the One Supreme Divinity. The doctrine which assumed great importance later - that custom has the force of law - is also exemplified by the twofold meaning, in Panini's Astadhyayi, attached to Dharma. Dharma is not only equivalent to Rta, primordial law, but also denotes custom (acara) as in the later Dharma Sutras."